by Kevin

Blue Origin's Lunar Lander Mark II concept.

A New Radio

In the summer of 2024 I was delighted to sign a contract with Blue Origin to help them develop the radios for their manned Lunar Lander. The design was just a sketch at that point, but with an aggressive development schedule, there was no time to waste. Time to roll up the sleeves.

Elaborate Performance Requirements

Communications devices operating in cisluar space must work with a variety of platforms, including:

• NASA's Tracking and Data Relay Satellite System (TDRSS)
• The Lunar Gateway space station
• EVA's, rovers, etc.

NASA has specifications for each of these platforms that run to hundreds of pages. They spell out scores of waveforms, data rates, transmit frequencies, forward error correction schemes, and so forth.

My favorite was Regenerative Ranging, where two radios can cooperate to make a sort of synthetic radar return and determine an approaching spacecraft's range and velocity.

I dove in* to help the systems engineers evaluate these waveforms, and to inform our tradeoffs by describing how they could be implemented on an FPGA.

Leading-Edge Technology

Do a stock image search for "leading-edge technology," and this is the sort of stuff you'll find.

We had new hardware to design from the circuit boards up. This meant choosing an FPGA device rated for space operations. We also needed digitizers with high-enough sample rates to operate at L-, X- and Ka-bands.

How high? We had to figure that out. Now I'm doing RF frequency planning, too!

In this case, "leading-edge technology" wasn't just a buzzword. We ended up relying on devices that were only just coming to market, with sampling rates in the tens of gigahertz. Exciting times.

A Candle in the Darkness

My final task on this short contract was to demonstrate some of this technology in hardware. Using a development board for a Zynq MPSoC, and another for a 10-GHz digitizer, I created a prototype transmitter that generated a QPSK signal at L-band, featuring:

• DSP resampling from 10 MS/sec to more than 750 MS/sec
• Onboard clock generation at multiple frequencies to support the DSP
• A JESD-204c link to feed the transmitter
• The complete AXI control architecture to load message contents, configure IP, etc.

The result was a perfect little QPSK signal coming out at 1.8 GHz. "It ain't real 'till you see it in hardware!"